Currently, the fastest growing areas of high performance liquid chromatographic separations are in the areas of biomolecule separations and liquid chromatography-mass spectrometry (LC-MS). While the last few decades have seen phenomenal progress in mass spectrometry, the shortfalls inherent in the separations coupled to the mass spectrometer still present considerable barriers to accessing the full information content in biological samples. Biomolecule separations are challenging because they present a variety of interaction modalities ranging from hydrophobic to polar to electrostatic. The proposed work addresses the urgent need for improved technologies for novel and more universal separation strategies for biopolymers (e.g., polypeptides, proteins, oligonucleotides) while simultaneously enabling characterization of solute/ionic liquid interactions. The objective of the proposed work is to integrate the emerging field of ionic liquids into novel separation strategies for biomolecular separations with the goal of providing a rapid method for assessing ionic liquids/target analyte interactions a new class of stationary phases enabling separations of complex biomolecular mixtures. We hypothesize that the proposed selectors will provide multimodal retention for the separation of a wide variety of biomolecular analytes. Two specific aims will address this hypothesis: 1. CE Studies of Ionic Liquid Selectors. Capillary electrophoresis will be used to rapidly screen for ionic liquids/selected analyte interactions. We will relate migration data to ionic liquid/analyte affinity. 2. LC Studies of Ionic Liquid Selectors. Retention data will be obtained on the proposed HPLC sorbents beginning systematically with small molecules (e.g., aromatics, nucleotides, amino acids) and extending to larger molecules (e.g., peptides, polynucleotides) as the separation space encompassed by this new media is mapped out.